Guides

Pincode autofill and IFSC lookup in a Flutter app

Fill in district and state from a pincode, check an IFSC code and show a company logo in Flutter, with the http package and no API key.

By Dharun Ashokkumar · published 2026-11-11

Address and bank forms in Indian apps ask for the same things: a pincode that should fill in the district and state, and an IFSC code that should show the bank and branch. Both are one GET request, with no key.

Add the http package

flutter pub add http

Pincode to district and state

import 'dart:convert';
import 'package:http/http.dart' as http;

class Place {
  final String district, state;
  final List<String> offices;
  Place(this.district, this.state, this.offices);
}

Future<Place?> lookUpPincode(String pincode) async {
  if (!RegExp(r'^[1-9]\d{5}$').hasMatch(pincode)) return null;
  final response = await http.get(Uri.parse('https://api.dharun.dev/v1/pincode/${pincode}?utm_medium=guide'));
  if (response.statusCode != 200) return null;
  final data = jsonDecode(response.body)['data'];
  return Place(data['district'], data['state'],
      [for (final office in data['offices']) office['name'] as String]);
}

Call it when the field reaches six digits, and fill the district and state fields from the answer. A pincode often has several post offices; show them as choices for the locality.

The answer for 637001:

{ "data": { "pincode": "637001", "district": "Namakkal", "state": "Tamil Nadu",
  "offices": [ { "name": "Namakkal H.O", "type": "Head Office", "delivery": true } ] } }

Try it: https://api.dharun.dev/v1/pincode/637001?utm_medium=guide

IFSC to bank and branch

Future<String?> describeIfsc(String code) async {
  final ifsc = code.trim().toUpperCase();
  if (!RegExp(r'^[A-Z]{4}0[A-Z0-9]{6}$').hasMatch(ifsc)) return 'An IFSC is 11 characters, the fifth a zero.';
  final response = await http.get(Uri.parse('https://api.dharun.dev/v1/ifsc/${ifsc}?utm_medium=guide'));
  if (response.statusCode == 404) return 'No branch has this IFSC.';
  final data = jsonDecode(response.body)['data'];
  return '${data['bank']['name']}, ${data['branch']}, ${data['city']}';
}

The answer also says whether the branch takes NEFT, RTGS, IMPS and UPI, and gives its MICR code: https://api.dharun.dev/v1/ifsc/SBIN0000001?utm_medium=guide

A company's logo in a list

Logos are plain image addresses, so Image.network is enough:

Image.network('https://api.dharun.dev/v1/logos/TCS?format=png&size=64&utm_medium=guide', width: 32, height: 32)

An unknown name gets a lettered placeholder instead of an error, so a list never shows a broken image: https://api.dharun.dev/v1/logos/TCS?format=png&size=64&utm_medium=guide

Limits

No key is needed. Without one, an address may make a few hundred requests a minute; a free key from https://api.dharun.dev/signup raises that. Cache the answers you reuse: pincodes and IFSC codes change rarely.

The code in this guide is MIT-0: copy it into anything, no credit needed. Updated 2026-11-11.

APIs used: Pincodes, IFSC and banks, Company logos.